Germination of Spores. 



Fig. 5. Tilletia tritici or Bunt of 'v1/heat. — a. Genninating spores with 

 septate promyceliuni bearing elongated conidia at apex x 300. h. Apex 

 of promyceliura from which the six conidia fused in pairs have become detached 



X 250. c. Conidia detached and fused in pairs, and some bearing sickle- 

 shaped conidia x 400. d. Mycelium like a tuft of mould produced from 

 conidium and bearing sickle-shaped conidia in all stages of development 



X .350. (After Brefeld.) 



Effect of Light and Darkness on Germination. 



I tested the germination of some of the more rapidly germinating spores, 

 such as those of Ustilago readeri in light and in darkness. Spores were taken 

 from plants of Danthonia penicillata, collected on 6th December, 1908, and 

 placed on sUdes in ordinary tap water on 6th January, 1909. Some were 

 kept under a bell- jar exposed to the light and others in a seed germinator in 

 which the light was excluded, but the air admitted. Both were kept in the 

 same room, the only difference being the presence or absence of light. The 

 experiment was repeated several times and invariably liglit was proved to 

 favour germination. 



In one experiment, the slides were examined after five hours, and while a 

 few of the spores exposed to the light had germinated, none had done so in 

 the dark. After twenty-four hours, they were again examined, and the great 

 majority of the spores had germinated in the light, while only a few had ger- 

 minated in the dark. In the light, promycelia wer<^ formed which sometimes 



